Bolt anchorage



T. c. scHENK 2,524,480

Bour ANcHoRAGE Oct. 3, 1950 Filed Nov. 20l 1948 lNVENTOR Patented ct. 3,1950 jUNITED S1`A"II 3Sv PATENT OFF-ICE' i t 2,524,480 j" y "l BOLTANCHORAGE Tamis C. Schenk, Richmond Hill, N. Y.

Application November 20, 1948, Serial No. 61,249

1 Claim (Cl. 85-32) This invention relates to anchorages for bolts andother threaded elements in concrete or similar plastic masses. An objectof the invention is to provide a device of this character which willthreadably receive the bolt and hold it rmly in place under hardconditions of service.

I am aware that prior to the present invention, eiiorts have been madeto embed in concrete masses, threaded spirals or helicals for thereception of the threaded end portions of bolts or like elements, andthe primary object of the present invention is to provide a threadedanchorage of such a character which will be, because of its improveddesign and construction more firmly anchored in the concrete mass sothat its dislodgment will be virtually impossible without destruction ofthe surrounding portions of the concrete in which it is embedded.

The invention further contemplates the provision of an article of thischaracter which can be speedily and economically made in quantity; whichcan be readily placed in position, and after the concrete has hardenedor set, will act as a rm and secure anchorage for the bolt.

These and other objects are attained by the invention, a more particulardescription f which will be hereinafter set forth and pointed out in theclaim appended hereto.

In the accompanying drawing, wherein an illustrative embodiment of theinvention is disclosed, Fig. 1 is a vertical sectional View through apart of a concrete mass showing the anchorage embedded therein and inengagement with the threaded portion of a bolt or similar threadedmember; Fig. 2 is an end view of the helical anchorage; Fig. 3 is a sideelevation of the same, and Fig. 4 is a face View of the metallic stripfrom which the coil or helix is formed.

Referring to the embodiment of the invention illustrated in the drawing,the anchorage is preferably formed from an elongated strip I of flatsheet metal of the form generally shown in Fig. 4. The length of thestrip from which the coillike anchorage is produced is, of course,dependent upon the desired length of the anchorage. In the form shown,the strip is provided with one longitudinal straight edge 2, theopposite edge 3 being undulated or formed with decidedly flat, spacedserrations. The strip formed as above described is Wound or shaped intohelical or spiral form, as clearly shown in Fig. 3. The helix or spiralso produced has its inside diameter or inner edge composed of thestraight edge 2 of the strip I and hence the inside diameter of the coil2 or helix, or the bore thereof, will be of uniform or constantdiameter.

The diameter of the coil thus formed will, of course, be that intendedto permit of threadable engagement with the threaded portion 5 at theend of a bolt 6 or other threaded element, and the length of the coilwill be that required to accommodate the threaded portion of the bolt.At one end, the end convolution of the coil is inwardly bent ordistorted as shown at 'l to form a limiting abutment for the pointed endof the bolt 6.

:It will be noted that the undulated edge 3 of the strip I is that whichforms the outer edge of the formed coil or helix, and as a result, theoutside diameter of the coil or helix is varied. That is to say, theshape of the coil is that of a plurality of frusto-conical membersconnected endwisely. It will be also noted that the convolutions of thehelix or coil are spaced apart, acy cording to the threads to beaccommodated, and that concrete in which the coil is embedded can enterbetween these convolutions and rest against the flat faces 9 thereof.

When an anchorage coil of this character is embedded in a concrete mass,the concrete will flow around the same and enter between theconvolutions of the coil as well as around the undulating surfaces denedby the outer edge of the coil.

The arrangement described is such that it is impossible to withdraw thecoil out of the concrete by axial movementpf the coil as well asextremely diicult, if not impossible, to rotate the coil in the concretemass. The conical disposition of the coils of the helix tends to furnisha positive bearing on a larger area of con- -crete and insures a betterlling of the voids between the turns in the narrow parts of the coil.

While I have herein described the strip from which the coil is made asbeing fabricated from at metal, it is apparent that it might be other-Wise formed, as for example, from wire made possibly triangulated incross-sectional shape and having one edge undulated as described withrespect to the embodiment shown in the drawing.

While I have herein described one embodiment o f the invention, it isobvious that the same is not to be restricted thereto but is broadenough to cover all structures coming within the scope of the annexedclaim.

What I claim is:

An anchorage for insertion in concrete or material of like charactercomprising, a iiat metal strip having a straight lengitedinal aise and e3 longitudinal edge of undulated form, said strip REFERENCES CITED beingcoiled into a spiral having spaced-apart The following references are ofrecord in the convolutions, the outside diameter of the coiled me ofthis patent:

strip being gradually increased or decreased in diameter according tothe undulations of said 5 UNITED STATES PATENTS outside edge, thestraight edge of the strip form- Number Name Date ing the inside edge ofthe spiral and providing a 163,485 Hansen May 18, 1875 constant anduniform inside diameter for said 240,780 Smith Apr. 26, 1881 spiral andadapted to form a spiral thread fOr a 271,929 Seybert Feb. 6, 1883threadedrmember; inserted within the coil. f 10v 1,230,603 Richmond`June 19, 1917 1,311,646 Gordon June 29, 1919 TAMIS C. SCHENK.A I2,439,685 Findley Apr. 13, 1948

